The present invention relates generally to covering or sealing fuses of a semiconductor device.
As is known, many semiconductor dice are typically manufactured on a single semiconductor wafer. Once manufactured, the dice are typically subjected to a series of tests. These tests typically begin with initial gross functionality testing followed by more exacting testing, including, for example, burn-in testing. Typically, initial gross functionality tests are performed while the dice are in wafer form, and subsequent more exacting tests are performed on individual dice after they are singulated from the wafer. It should be noted, however, that the dice are sometimes subjected to the further testing while in wafer form. Often, although not always, the dice are packaged, at least partially, prior to some or all of the testing that follows the initial gross functionality testing.
Fuses may be formed on a semiconductor die that allows a defective circuit on the die to be replaced by a redundant or replacement circuit on the die. For example, fuses are often used on semiconductor memory die to replace a memory cell or column or row of memory cells found through testing of the die to be defective. Activation of a fuse disconnects the defective cell or column or row of cells and connects replacement cells, rows, or columns. A laser may be used to activate a fuse, which often involves cutting a fusible link on the die, but other fuse arrangements may be used.
Because dice are typically packaged before all testing of the dice has been completed, the fuses can only be used to replace defective circuits found during testing that occurs before packaging. This is because the packaging typically covers the fuses, making the fuses inaccessible after packaging has been applied. Even if the dice are not packaged or their packaging does not cover the fuses, the fuses nevertheless should be covered before the dice are used in their final applications to protect the fuses from environmental or other effects that might degrade the fuses and possibly cause the die to malfunction.